U.S. patent application number 10/419800 was filed with the patent office on 2004-01-08 for image forming device.
This patent application is currently assigned to SAMSUNG ELECTRONICS CO., LTD.. Invention is credited to Ahn, Dong-Cheol.
Application Number | 20040005170 10/419800 |
Document ID | / |
Family ID | 29997425 |
Filed Date | 2004-01-08 |
United States Patent
Application |
20040005170 |
Kind Code |
A1 |
Ahn, Dong-Cheol |
January 8, 2004 |
Image forming device
Abstract
An image forming device, including a charging unit to
electrically charge a surface of an organic photoconductive medium;
a light exposure unit to form an electrostatic latent image on the
surface of the organic photoconductive medium; a developing unit to
develop the electrostatic latent image formed with a developer; a
transfer roller to transfer an image developed by the developing
unit to a recording paper; a light array having a plurality of
light sources arranged in a predetermined pattern; a first light
path providing unit to form a light path to receive a first light
portion emitted from the light sources and to allow the light to be
projected on the organic photoconductive medium between the
developing unit and the transfer roller; and a second light path
providing unit to form a light path to receive a second portion of
the light emitted from the light sources and to allow the light to
be projected onto the organic photoconductive medium passing
through the transfer roller, thereby removing an electrostatic
latent image remaining on the surface of the organic
photoconductive medium.
Inventors: |
Ahn, Dong-Cheol;
(Youngin-City, KR) |
Correspondence
Address: |
STAAS & HALSEY LLP
SUITE 700
1201 NEW YORK AVENUE, N.W.
WASHINGTON
DC
20005
US
|
Assignee: |
SAMSUNG ELECTRONICS CO.,
LTD.
Suwon-City
KR
|
Family ID: |
29997425 |
Appl. No.: |
10/419800 |
Filed: |
April 22, 2003 |
Current U.S.
Class: |
399/128 ;
399/296 |
Current CPC
Class: |
G03G 21/00 20130101;
G03G 15/169 20130101 |
Class at
Publication: |
399/128 ;
399/296 |
International
Class: |
G03G 015/16; G03G
021/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 2, 2002 |
KR |
2002-38053 |
Claims
What is claimed is:
1. An image forming device comprising: an organic photoconductive
medium; a charging unit to electrically charge a surface of the
organic photoconductive medium; a light exposure unit to form an
electrostatic latent image on the surface of the organic
photoconductive medium; a developing unit to develop the formed
electrostatic latent image with a developer; a transfer roller to
transfer the developed image to a recording paper; a light array
comprising a plurality of light sources arranged in a predetermined
pattern to emit light; a first light path providing unit to provide
a first light path to receive a first portion of the light emitted
from the light sources and to allow the received first portion
light to be projected on the photoconductive medium between the
developing unit and the transfer roller; and a second light path
providing unit to form a second light path to receive a second
portion of the light emitted from the light sources and to allow
the received second portion light to be projected onto the
photoconductive medium passing through the transfer roller, thereby
removing the electrostatic latent image from the surface of the
organic photoconductive medium.
2. The image forming device of claim 2, wherein the first and
second light path providing units are optical fibers to advance the
received first and second portion light by an inner total
reflection.
3. An image forming device, comprising: a photoconductive medium
having an electrostatic image developed thereon with a developer; a
transfer unit to transfer the developed image to a recording
medium; a light source to emit light; and a light path unit to
transfer the emitted light to the photoconductive medium on
opposite sides of the transfer unit.
4. The image forming device of claim 3, wherein the photoconductive
medium rotates to bring the developed image in contact with the
transfer unit.
5. The image forming device of claim 4, wherein the light path unit
comprises: a first light path unit to transfer the emitted light to
the developed image prior to contacting the transfer unit; and a
second light path unit to transfer the emitted light to the
photoconductive medium after the image has been transferred.
6. The image forming device of claim 5, further comprising: a
radiation exposure unit to expose radiation onto the
photoconductive medium to thereby form the electrostatic image with
an electric potential.
7. The image forming device of claim 6, wherein the first light
path unit reduces a difference between the electric potential of
the electrostatic image and an electric potential of a non-image
area of the photoconductive medium.
8. The image forming device of claim 7, wherein the first light
path unit reduces a force between the developer and the
electrostatic image.
9. The image forming device of claim 5, further comprising: a
plate, between the photoconductive medium and the first light path
unit, to prevent the developer from passing from the
photoconductive medium to the first light path unit.
10. The image forming device of claim 5, wherein the first light
path unit comprises a light projecting end to project the
transferred light and disposed at a position to prevent
contamination from the developer which passes from the
photoconductive medium.
11. The image forming device of claim 7, wherein the second light
path unit makes uniform the electric potential of the electrostatic
image and the electric potential of the non-image area of the
photoconductive medium.
12. The image forming device of claim 5, wherein the first and
second light path units are optical fibers.
13. The image forming device of claim 5, wherein the first and
second light path units each comprises an end, the ends being
integrally in contact with each other.
14. The image forming device of claim 5, wherein the first and
second light path units each comprise a projection end to project
the transferred light to the photoconductive medium, and the
projection ends comprise slits to regulate an amount of the
projected light.
15. The image forming device of claim 3, wherein the light path
unit divides the emitted light.
16. The image forming device of claim 3, further comprising a
plurality of the light sources.
17. An image forming device, comprising: a photoconductive medium
having an electrostatic image developed thereon with a developer; a
transfer unit to transfer the developed image to a recording
medium; a light source to emit light; and a divider to divide the
emitted light onto the developed image and the transferred image.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of Korean Application
No. 2002-38053, filed Jul. 2, 2002, in the Korean Intellectual
Property Office, the disclosure of which is incorporated herein by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an image forming device,
and more particularly, to an image forming device which projects
light emitted from a light source onto a predetermined area of a
photosensitive medium, thereby improving an image transfer
efficiency and removing a remaining electrostatic latent image.
[0004] 2. Description of the Related Art
[0005] Image forming devices such as photocopiers, printers,
facsimile machines, and multi-function machines are used to print
images. Among these devices, printers are most frequently used to
reproduce computer-processed information.
[0006] FIG. 1 is a schematic view showing a conventional image
forming device.
[0007] Referring to FIG. 1, an image forming device includes a
charging unit 10, an organic photoconductive drum 20, a light
exposure unit 30, a developing unit 40, a transfer roller 50, a
pre-transfer lamp 60, and a latent image removing lamp 70.
[0008] A charging roller 10a is electrically charged by a voltage
and is rotated to electrically charge a photosensitive medium
coated along an external circumference of the organic
photoconductive drum 20. Then, an electrostatic latent image is
formed on the organic photoconductive drum 20 exposed to light
emitted from the light exposure unit 30. Next, the developing unit
40 develops the electrostatic latent image formed on the organic
photoconductive drum 20 by using a developer.
[0009] The transfer roller 50 transfers an image formed by the
developing unit 40 to a recording paper (not shown). The image
forming device fuses the image printed on the recording paper by
using a fusing unit (not shown) and discharges the paper.
[0010] Meanwhile, the pre-transfer lamp 60 is positioned at a
position to project the light onto an area of the organic
photoconductive drum 20 that corresponds to the area between the
developing unit 40 and the transfer roller 50. The pre-transfer
lamp 60 projects the light to the developer coated on the surface
of the organic photoconductive drum 20 to thereby increase an
electric potential of the developer. Accordingly, a binding force
of the developer decreases and thus image transfer efficiency is
improved. At this time, the light emitted from the pre-transfer
lamp 60 is focused on the organic photoconductive drum 20 by a lens
62 which corresponds to the pre-transfer lamp 60.
[0011] The pre-transfer lamp 60 may be disposed to project the
light onto a backside of the recording paper (not shown). At this
point, since the transmissivity of the light varies depending on
features of the recording paper, there may be a variation in the
transfer efficiency. In consideration of this fact, the
pre-transfer lamp 60 may be disposed at a position A to project the
light directly onto the surface of the organic photoconductive drum
20 in the same direction as the dotted line of FIG. 1.
[0012] Meanwhile, in order to form a new electrostatic latent image
on the organic photoconductive drum 20, it is necessary to remove
the remaining latent image (a remaining electric potential) that
still remains after passing through the transfer roller 50. The
latent image removing lamp 70 projects light onto the area of the
organic photoconductive drum 20 that has already passed the
transfer roller 50 to remove the remaining latent image.
[0013] As described above, such a conventional image forming device
must separate the pre-transfer lamp 60 and the latent image
removing lamp 70 to maintain transfer efficiency and remove the
remaining latent image to improve the image quality.
[0014] FIG. 2 is a view showing the arrangements of the
pre-transfer lamp 60 and the latent image removing lamp 70.
[0015] Referring to FIG. 2, the pre-transfer lamp 60 and the latent
image removing lamp 70 are structured so that a plurality of LED
emitting elements are arranged on a separate PCB base plate in a
predetermined pattern, and provided with a power via a separate
power cable 90.
[0016] That is, the conventional image forming device must include
separate light emitting elements to project the light to the
organic photoconductive drum 20, thereby improving the transfer
efficiency and the image quality. The light emitting elements
require a separate base-plate to be arranged thereon and the
separate power cable 90 to supply the power therethrough.
Accordingly, there are problems due to complicated structure and
increased cost.
SUMMARY OF THE INVENTION
[0017] Accordingly, it is an aspect of the present invention to
solve the above problems in the conventional apparatus.
[0018] It is another aspect of the present invention to provide an
image forming device capable of dividing the light emitted from a
light source, a first part being projected to an area of an organic
photoconductive drum corresponding to the area between a developing
unit and a transfer roller in order to improve an image transfer
efficiency, a second part being projected to remove a latent image
remaining on the organic photoconductive drum after being
developed.
[0019] Additional aspects and advantages of the invention will be
set forth in part in the description which follows and, in part,
will be obvious from the description, or may be learned by practice
of the invention.
[0020] The foregoing and/or other aspects are achieved by providing
an image forming device including an organic photoconductive
medium; a charging unit to electrically charge a surface of the
organic photoconductive medium; a light exposure unit to form an
electrostatic latent image on the surface of the organic
photoconductive medium; a developing unit to develop the formed
electrostatic latent image with a developer; a transfer roller to
transfer the image developed to a recording paper; a light array
including a plurality of light sources arranged in a predetermined
pattern to emit light; a first light path providing unit to provide
a first light path to receive a first portion of the light emitted
from the light sources and to allow the received light to be
projected on the photoconductive medium between the developing unit
and the transfer roller; and a second light path providing unit to
form a second light path to receive a second portion of the light
emitted from the light sources and to allow the received light to
be projected onto the photoconductive medium passing through the
transfer roller, thereby removing the electrostatic latent image
from the surface of the organic photoconductive medium.
[0021] The first and second light providing units may be optical
fibers to advance the incident light by an inner total
reflection.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] These and/or other aspects and advantages of the invention
will become apparent and more readily appreciated from the
following description of the preferred embodiment, taken in
conjunction with the accompanying drawings of which:
[0023] FIG. 1 is a schematic cross-sectional view showing a
conventional image forming device;
[0024] FIG. 2 is a view showing arrangements of the pre-transfer
lamp and the latent image removing lamp of FIG. 1; and
[0025] FIG. 3 is a schematic cross-sectional view showing an image
forming device according an embodiment of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] Reference will now be made in detail to the present
preferred embodiment of the present invention, examples of which
are illustrated in the accompanying drawings, wherein like
reference numerals refer to like elements throughout.
[0027] FIG. 3 is a cross-section view showing an image forming
device having a light path providing unit according to an
embodiment of the present invention.
[0028] Referring to FIG. 3, the image forming device includes a
charging unit 100, an organic photoconductive drum 110, a light
exposure unit 120, a developing unit 130, a transfer roller 140, a
light array 150, and a light path providing unit 160.
[0029] The charging unit 100 electrically charges a surface of the
photosensitive drum 110 employed as a photosensitive medium to form
a uniform electric charge layer. That is, a charging roller 100a
disposed in the charging unit 100 electrically charges an external
circumference of the organic photoconductive drum 110 uniformly by
being rotated.
[0030] The light exposure unit 120 projects the light onto the
surface of the organic photoconductive drum 110 electrically
charged by the charging unit 100 and forms an electrostatic latent
image.
[0031] The developing unit 130 develops the electrostatic latent
image formed on the organic photoconductive drum 110 by the light
exposure unit 120 with a developer having an electric charge.
[0032] The transfer roller 140 rotates in contact with the organic
photoconductive drum 110 and transfers the developed image of the
organic photoconductive drum 110 to the incoming recording paper
(not shown).
[0033] The light array 150 is structured in a manner that a
plurality of light sources 150a are arranged on a base-plate 150b
in a predetermined pattern in the same manner as that of FIG. 2.
The light sources 150a may be light emitting elements such as LEDs,
and are supplied with a power from a power supplying portion (not
shown) under the control of a controller (not shown) when a
printing operation begins to be performed.
[0034] The light path providing unit 160 provides light paths to
receive the light emitted from the light sources 150a and to
project the light onto the organic photoconductive drum 110
therethrough. One of the light paths allows the light to be
projected to an area of the organic photoconductive drum 110 that
passes through a developing process and is placed ahead of a
transfer process. Another light path allows the light to be
projected onto an area of the organic photoconductive drum 110
passing through the transfer process.
[0035] The light path providing unit 160 has a first light path
providing unit 162 and a second light path providing unit 164.
[0036] The first light path providing unit 162 provides a light
path to receive a part of the light emitted from the light sources
150a and to project the light onto an area of the photosensitive
drum 110 that is placed between the developing unit 130 and the
transfer roller 140.
[0037] In order to reduce an electric potential difference between
an area exposed to the light by the light exposure unit 120 and a
non-exposed area prior to the transfer process, the first light
path providing unit 162 provides the light path to allow the light
to be projected to the organic photoconductive drum 110 between the
developing unit 130 and the transfer roller 140.
[0038] The first light path providing unit 162 allows the light to
be projected onto the developer coated on the surface of the
organic photoconductive drum 110 that is placed between the
developing unit 130 and the transfer roller 140, thereby increasing
the electric potential of the developer. Accordingly, the
binding-force of the developer increases and thus the image
transfer efficiency is improved.
[0039] For example, if the light is projected onto the organic
photoconductive drum 110 having a surface electric potential of
-800V through the first light path providing unit 162, the surface
electric potential of the photosensitive drum 110 increases to
-200V. Accordingly, the surface electric potential of the organic
photoconductive drum 110 corresponding to the area not exposed to
the light increases such that the binding-force of the developer
decreases. Therefore, transfer efficiency is increased.
[0040] Reference numeral 170 indicates a protection guide plate to
prevent the first light path providing unit 162 from being
contaminated by falling developer during the developing
process.
[0041] A light projecting end may be disposed on the first light
path providing unit 162 at a position to prevent contamination
thereof from the falling developer during a developing process.
That is, the first light path providing unit 162 has the light
projecting end disposed at a position corresponding to the
pre-transfer lamp 60 disposed at position A as shown in FIG. 1.
[0042] The second light path providing unit 164 provides a light
path to allow the other part of the incident light from the light
sources 150a to be projected onto a predetermined area of the
organic photoconductive drum 110 passing through the transfer
roller 140, thereby removing the remainder of the latent image.
[0043] The light is projected onto the surface of the organic
photoconductive drum 110 passing through the transfer roller 140
through the second light path providing unit 164, thereby removing
a remaining latent image. Accordingly, the surface electric
potential of the organic photoconductive drum 110 becomes uniform.
Accordingly, an overlapped image that may be caused by the
remaining latent image is prevented and thus the image of high
resolution can be obtained.
[0044] In FIG. 3, the first and second light path providing units
162 and 164 use an optical fiber to advance the incident light from
the light sources 150a by an inner total reflection. However,
anything that is capable of advancing the incident light from the
light sources 150a by the inner total reflection in a predetermined
direction may alternately be used.
[0045] Meanwhile, the first and second light path providing units
162 and 164 may have ends of surfaces thereof opposing the light
sources 150a integrally formed with each other by being in linearly
contact with each other. Also, the first and second light path
providing units 162 and 164 may include light amount regulating
slits (not shown) disposed at their light projecting ends, to
regulate the amount of the light emitted from the light sources
150a.
[0046] The image forming device according to the embodiment of the
present invention has a structure to divide and utilize the light
emitted from the light sources 150a. Accordingly, it has a
simplified structure.
[0047] Although an embodiment of the present invention has been
shown and described, it will be appreciated by those skilled in the
art that changes may be made in this embodiment without departing
from the principles and spirit of the invention, the scope of which
is defined in the claims and their equivalents.
* * * * *